A massive burst of inter-stellar radiation may have stuck the Earth in the middle ages, researchers have announced.
It is thought that the explosion occurred when two black holes or neutron stars collided somewhere in the Milky Way.
The resultant gamma ray burst sent shockwaves through the galaxy, and hit our planet in the eighth century AD, the German team behind the study told the BBC.
It is the latest development of the theory that the middle ages saw a spike in the amount of radiation that can now be found in trees and rocks.
In 2012 a Japanese team found that ancient cedar trees had high levels of carbon-14, an isotope which is created when radiation strikes atoms in our upper atmosphere.
Further research on radiation found in ice in the USA pinned the explosion down to between 774 and 774 AD.
It was thought a supernova explosion, or possibly a very large solar flare or Coronal Mass Ejection could have been the cause.
But the German team led by Professor Ralph Neuhauser, from the Institute of Astrophysics at the University of Jena now claims an explosion deep in the Milky Way is likely to blame.
Speaking to the BBC, he said that a "very, very explosive" event about 3,000 to 12,000 light-years away was probably the cause of the radiation spike.
So why - as Engadget's Daniel Cooper put it on Twitter - wasn't there a sudden rise in the number of medieval Hulks stalking Carolingian Europe - or a rise in illness?
Because, Professor Neuhauser said, most of the radiation was absorbed by the atmosphere, so that only small traces eventually landed on the surface. It was also unlikely that any visible light hit the Earth.
So there you have it, comic book writers: you finally have a scenario for your medieval X-Men story.Oh, wait...UPDATE: Interestingly, it has been pointed out to HuffPost by Oxford Masters student Alex Franklin that the Anglo Saxon Chronicle entry for 774 AD contains the following line:

"This year also appeared in the heavens a red crucifix, after sunset; the Mercians and the men of Kent fought at Otford; and wonderful serpents were seen in the land of the South-Saxons."

It's not likely to be related, but it's an interesting twist anyway. Also, if anyone sees any wonderful serpents too, let us know?